Proof
Increasing your highway cruising speed from 55mph (90km/h) to 75mph (120km/h) can raise fuel consumption as much as 20%. You can improve your gas mileage 10 - 15% by driving at 55mph rather than 65mph (104km/h).
Note how quickly efficiency drops after 60 mph.
to prove my other point about the tires
Make sure your tires are properly inflated to prevent increased rolling resistance. Under-inflated tires can cause fuel consumption to increase by as much as 6%. Operating a vehicle with just one tire under-inflated by 40 kPa can reduce the life of the tire by 10,000 km and increase the vehicle's fuel consumption by three per cent.
Check tire pressure at least once a month, when the tires are 'cold' (i.e. when the vehicle has not been driven for at least three hours or for more than 2km). Start by checking tire pressures in your driveway. Note any tire that is underinflated, and then drive to the nearest gas station to add air. Check tire pressures again at the station, and inflate the low tires to the same level as the others (these will likely have higher pressure than they did in the driveway, since the tires have heated up.) Radial tires can be under inflated yet still look normal. Always use your own tire gauge for consistent results. On average, tires lose about 1 psi per month and 1 psi for every 10 degree drop in temperature.
Refer to
http://eartheasy.com/live_fuel_efficient_driving.htm
Last edited by
Val on December 13th, 2005, 10:06 am, edited 1 time in total.
